I've reclaimed an old cistern as storage space in my basement. I'd like to smooth the floor down a bit and give it a coat of paint.
The floor appears to be 4" of good solid concrete and what parts of it I've exposed seems to fairly smooth. But the inside of the cistern was lined with two courses of brick, a parge coat, and tar. The floor wasn't a concern during construction [1940's?] so it has lumps, bumps, gobs of mortar and tar in varying thicknesses all over it.
I have a Bosch demo hammer with a 1" chisel bit & that does a pretty good job of bringing up the old mortar, but it takes a soft hand to not start eating into the concrete.
I see a few different possibilities in the Bosch department-- a scaling chisel?
I've never used any of these. Can anyone recommend or warn me away from them?
Or is there a better tool I could rent?
The floor is only 6x8 feet so I don't need a huge or powerful tool. I'm also not looking for a glass smooth finish, just something smooth enough to walk on and clean enough to take deck paint.
Thanks, Jim